The present invention relates in general to maintenance testing of telecommunications network equipment, and, more specifically, to scheduling of tests between large numbers of network nodes using test equipment having multiple channels for conducting a plurality of simultaneous tests.
In order to maintain a high level of quality of service in a telecommunications network, various standard equipment tests have been defined such as those in the Telcordia standard GR-822. In order to quickly identify all malfunctions that may compromise the quality of service, automated testing needs to be thorough and efficient so that all network resources are checked in the least amount of time. A typical telecommunications network has many functioning elements connected in a complex architecture. A nationwide long distance network, for example, may have about fifty switches interconnected by several thousand Intermachine Trunk (IMT) groups. Each IMT consists of many T1 spans (DS-1) and each DS-1 in turn contains 24 trunk circuits (DS-0). Tests that operate at the trunk circuit level (e.g., echo canceller testing) require many thousands of individual automated tests.
Testing units utilized in test the system are standalone devices capable of several different kinds of automated tests. Each testing unit is equipped with one or more T1 cards to handle multiple channels so that it can do many simultaneous tests. In a typical network, at least one respective testing unit is connected to each switch or other node through Automatic Trunk Routing (ATR). Most trunk circuit tests involve both switches connected by the DS-0 line and the individual testing units connected to the switches. Each test typically involves a test call being placed over the trunk circuit, which results in that trunk circuit being unavailable to carry any customer calls during the test. Therefore, tests are scheduled only during predefined “maintenance windows” coinciding with the least busy times for the network. Since switches may be in different geographic locations spanning different time zones, the maintenance windows may not start or end together at both ends of a particular trunk group.
Scheduling of automated tests should make full use of available testing resources. For example, the simultaneous testing capabilities of the testing units should be fully utilized. Scheduling should ensure that there are no conflicts in the assigned tasks. Even though testing may be occurring simultaneously on unrelated trunk groups, tests must be scheduled in such a way that a testing unit is not overloaded and is not directed to perform incompatible tasks. Scheduling must also be achieved in such a way that the ability of the network to meet quality of service performance during testing is not impaired. Due to the complexity of the network interactions and the large number of permutations of potential testing events, prior art scheduling techniques have failed to meet the foregoing goals. Prior art manual scheduling methods have only managed to test about 15% of a 50-switch long distance network in a two week time period. Testing of a full network would have taken even longer.